Sky & Telescope - March 2025 - 15

Worldwide, the number of extreme wildfires more than
doubled between 2003 and 2023. Observatories faced threats
at both the start and end of that time span. In Australia, for
instance, the extreme bushfire season of 2003 completely
destroyed the Mount Stromlo Observatory near Canberra,
wiping out all its research telescopes. In 2023, the worst fire
in 40 years reached the observatory on the slopes of Mount
Teide on Tenerife in the Canary Islands, forcing firefighters to
battle the flames right under the telescope domes.
Even after the blaze is quenched, wildfires can still disrupt
observations for long periods. Domes are kept shut to prevent
ash from blowing inside and damaging instruments. Smoke
and haze can significantly reduce nighttime sky clarity for
weeks. The largest wildfires are powerful enough to inject
smoke directly into the stratosphere, where it can travel vast
distances and persist for long periods of time. That was the
case in June 2023, when the smoke from fires in Canada
reached New York.
Two main causes lie behind this increase in the frequency
of intense fires. One is climate change. The fire season is
becoming longer, meaning there are more days when meteorological
factors are conducive to wildfires. There are long
droughts and record-breaking temperatures. The atmosphere
is also changing, as higher temperatures lead to more unstable
conditions. An unstable atmosphere acts like a chimney,
enabling hot, smoky air to rise more easily, pulling in fresh,
oxygen-rich air from the surroundings and fueling flames. As
a result, a fire's spread accelerates.
An unstable atmosphere also forms more storms, which
may produce lightning. A recent study shows that the number
of lightning strikes could increase by 40% by the end of the
century, leading to even more wildfires.
A second factor, however, is the way society has managed
fires in recent decades. Fires are part of the natural cycle of
the forest, removing undergrowth and older trees. Sometimes,
the focus has been put on suppressing all fires; other times,
neglect or negligence has left vegetation uncontrolled. Both
approaches leave forests chockful of flammable material,
making them more susceptible to large, destructive blazes -
regardless of whether the spark is natural or humanmade.
" It's not why a fire starts that is worrying, but why it cannot
be stopped, " says Andrea Duane (University of California,
Davis) who studies the interaction between wildfires, landscape,
and climate. " Things have always burned, but recently
we found that our most advanced extinction methods are not
enough to control these fires. " The solutions are different for
each region, Duane says, but at this point adapting management
practices to the new reality looks like the best strategy.
Amateur astronomers, dispersed in remote, forested areas,
are arguably more exposed than their professional counterparts.
In recent years, " the forests are burning, observatories
are being threatened, and amateur star parties are getting
badly smoked or canceled outright, " says S&T Contributing
Editor Ken Hewitt-White, an amateur based in southern British
Columbia, Canada.
30%
20%
10%
0 %
1996 2000 2004 2008 2012 2016 2020
Year
pSUMMIT WEATHER Over the last few decades on Mauna Kea, the
percent of nighttime observations during which meteorological conditions
exceeded the Keck Observatory's dome-closure criteria has risen.
Individual conditions have not necessarily changed significantly; rather,
the combination of conditions is worsening.
As a regular attendee of the Mount Kobau Star Party in
British Columbia, Hewitt-White has witnessed an increase in
the number of wildfires since the turn of the century. Smoke
and fire risk have become increasingly common threats. In
the last five years, the Mount Kobau party has been canceled
or delayed three times due to fire risks that threatened the site
or its access roads. Other events have suffered similar cancellations,
such as the Oregon Star Party.
Hewitt-White recalls a harrowing experience in 2015,
when a wildfire erupted near Mount Kobau and raced up the
slopes in the late afternoon. About 80 attendees had to hastily
pack their optical and camping equipment and flee down a
bumpy, winding gravel road. All escaped, " but it was terrifying, "
he says.
A Fogged Up Window to the Universe
Climate change also subtly deprives us of the sharpest views
of the cosmos. Astronomical observations rely on specific
atmospheric conditions - minimal light pollution, low
humidity, and a stable atmosphere - which climate change
may alter in complex ways. Professional telescopes are feeling
the pinch first.
Observatories hoard decades' worth of detailed weather
data, collected routinely during daily operations and site surveys.
Most of these data, however, remain largely unexplored
for climatic trends.
In 2020, exoplanet researchers Faustine Cantalloube and
Julien Milli (both now at the Institute for Planetary Sciences
and Astrophysics, Grenoble, France) tapped into this resource
for the first time. The astronomers were working at the
European Southern Observatory's Very Large Telescope (VLT),
located at the Paranal Observatory in Chile's Atacama Desert.
To detect the faint signals of distant exoplanets, they require
exceptionally sharp images.
However, they noticed that under certain atmospheric
conditions, the sharpness of the VLT images suffered. This
sk yand tele scope .o r g * MARCH 2025 15
BEATRIZ INGLESSIS / S&T, SOURCE: M. A. M. VAN KOOTEN AND J. G. IZETT /
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC 2022
Fraction of observations exceeding
dome-closure criteria
http://skyandtelescope.org
Sky & Telescope - March 2025

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